A landlocked navy is a naval force operated by a country that does not have a coastline. While these states are unable to develop a sea-going, blue-water navy, they may still deploy armed forces on major lakes or rivers. Such forces are often referred to as brown-water navies.
There are several reasons a landlocked country may choose to maintain a navy. If a river or lake forms a national border, countries may feel the need to protect and patrol that border with a military force. In some regions, roads may be unreliable or circuitous, and a river or lake may be the easiest way to move military forces around the country. Sometimes, possession of a body of water may actually be contested – for example, countries around the landlocked Caspian Sea have different views of how ownership should be divided.
Patrol boats of various types are the most common craft among landlocked navies. Some landlocked navies possess troop or vehicle transports, allowing ground forces to cross or travel along a lake or river.
The operation of military forces in lakes and rivers is not limited to landlocked countries. Many states maintain these forces in addition to their seagoing navy. They may be part of the same organisation (e.g. the Russian Caspian Flotilla) or not (e.g. U.S. Coast Guard).